ESTABLISHMENT OF AN INTERACTIVE MAP TO ASSESS KARST DEVELOPMENT AND ITS INFLUENCE ON GROUNDWATER QUALITY IN NORTHERN ARKANSAS

In the Ozark Plateaus of Arkansas, karst aquifers are an important source of drinking water. The prevalence of karst terrain —expressed at the surface by the presence of springs, caves, sinkholes, and other karst surface features—causes groundwater to be susceptible to contaminants that quickly enter the aquifers because of conduit flow and the intimate connection of surface and groundwater. Because of this connectivity, it is often assumed that areas of more highly developed karst—as indicated by a high density of karst features—may exhibit degraded water quality. This study attempts to quantify relationships between karst development and water quality which are not well documented.

In this study, karst feature density is used to define karst development in the Ozarks of Arkansas. Digitization of karst features from topographic maps using ArcGIS thus far has included more than 800 sinkholes, more than 500 springs, and about 50 caves to be used as metrics for karst development. The overall objective is to establish an interactive map of karst development and available water quality data that will provide a better understanding of the relative vulnerability of groundwater to contaminants. Geology, faulting, lineaments, and gaining or losing stream segments are being added to the karst-feature map. This interactive map of karst development with water quality data will be used to assess the vulnerability of karst groundwater systems to contamination in the Ozarks, which, in turn, will provide insight into controls on water quality and will enable improved management of drinking-water sources.